Re: [PATCH 20/24] task_diag: Only add VMAs for thread_group leader
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From: Oleg Nesterov <hidden>
Date: 2015-07-14 17:48:49
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On 07/06, Andrey Vagin wrote:
From: David Ahern <redacted> threads of a process share the same VMAs, so when dumping all threads for all processes only push vma data for group leader.
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quoted hunk ↗ jump to hunk
@@ -492,6 +493,13 @@ static int task_diag_fill(struct task_struct *tsk, struct sk_buff *skb, } if (show_flags & TASK_DIAG_SHOW_VMA) { + /* if the request is to dump all threads of all processes + * only show VMAs for group leader. + */ + if (req->dump_strategy == TASK_DIAG_DUMP_ALL_THREAD && + !thread_group_leader(tsk)) + goto done; +
This doesn't look right, group leader can be a zombie with ->mm == NULL,
if (i >= n) err = fill_vma(tsk, skb, cb, &progress, show_flags);
so this probably needs something like find_lock_task_mm(). Oleg.